Fluid mechanics question and the Bernoulli Equation

In summary, the conversation discusses a struggle in finding the solution for Q2 and Q3, where the pressure at point 1 and point 2 are being compared. The formula for calculating pressure is mentioned, as well as the fact that the pressure at point 2 is not equal to the pressure at point 1 due to differences in velocity. The OP also asks for help with Q3 and requests that the questions be typed out for clarity.
  • #1
Franklie001
49
7
Homework Statement
Fluid mechanics question and Bernoulli Equation
Relevant Equations
Q2 and Q3
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Good afternoon,

I am struggling to find the solution at Q2 and Q3. For Q2 the absolute pressure at point 1 is at the bottom of the tank, so do i need to use the formula P=Patm+qgh ? If using this formula I've got a bigger number than 100Pa.
Same issue for Q3, isn't the pressure at point 2 equal the one at point 1, being at the same height? The question mention that the answer should be within 500 Pa.

Thank you
 

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  • #2
Franklie001 said:
I am struggling to find the solution at Q2 and Q3
I suppose Q2 is in the first picture ?
I find it a struggle to even read the questions in the second picture. Can you type them out ? At least Q3 ?

Franklie001 said:
If using this formula I've got a bigger number than 100Pa
Yes, 105 + ##\rho g \Delta h\ ## is a lot more than 100. Is your answer not accepted ? I get the same. I resent that the dumb computer doesn't see units.

I also get the same for Q1 (almost :smile:: 16.27 kg/s)

Please post your work.

##\ ##
 
  • #3
The pressure at point 2 is not equal to the pressure at point 1. At point 2 (immediately inside the pipe) the velocity has built up in the approach to to the pipe (within the tank) from zero at point 1 (and other locations at the bottom significantly removed from the pipe entrance) to full pipe velocity at point 2. So the pressure at point 2 is significantly lower than at point 1.
 
  • #4
Hello Chet ! You apparently have been able to read Q3. But OP asks about Q2 (which is legible) as well.

##\ ##
 

1. What is fluid mechanics?

Fluid mechanics is a branch of physics that deals with the study of fluids (liquids and gases) and their behavior when in motion or at rest.

2. What is the Bernoulli equation?

The Bernoulli equation is a mathematical equation that describes the relationship between pressure, velocity, and height in a fluid. It states that as the velocity of a fluid increases, its pressure decreases, and vice versa.

3. How is the Bernoulli equation used in real-life applications?

The Bernoulli equation is used in various real-life applications, such as in aerodynamics, hydraulic engineering, and ventilation systems. It helps in understanding the flow of fluids and designing efficient systems.

4. What are the assumptions made in the Bernoulli equation?

The Bernoulli equation makes several assumptions, including the fluid being incompressible, non-viscous, and steady-state. It also assumes that there is no change in height or temperature along the flow path.

5. Can the Bernoulli equation be applied to all types of fluids?

No, the Bernoulli equation is only applicable to ideal fluids, which are non-viscous and incompressible. Real fluids, such as air and water, have some level of viscosity and compressibility, so the equation may not accurately describe their behavior.

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